Pinging (spark knock?) Lancer

Joined
Apr 11, 2019
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177
I have a Mitsubishi Lancer 2.0 that is pinging when it gets warm. I can hear it when giving it light gas, especially on a slight incline. Running on 87 made it sound like it was really bad for it. Putting 91 fuel in it seems to pretty much make it go away, although I can very faintly hear it at times still. However, the two shops I have taken it to have both said they "don't hear anything." I just don't understand how they can miss it. One of them said it's probably a heat shield rattling and one of them sprayed the in-take to clean the top of the valves because there was some carbon, cleaned the MAF sensor, and changed the spark plugs. No change in the pinging. Do you recommend I have someone dive deeper into this (especially when they claim they can't even hear the problem) or should I just run 91?
 
Just how much 91 Octane did you put into how much 87 Octane? You may be able to get away by using 89 Octane. It is very hard to say what the combined Octane is you are running.
 
Just how much 91 Octane did you put into how much 87 Octane? You may be able to get away by using 89 Octane. It is very hard to say what the combined Octane is you are running.
I've done multiple tanks of 91 just to see. I could try 89 but my bigger question is, is running higher octane fuel the only solution?
 
Is it worse in hot weather? Does it do it more when the engine is cold or warmed up?

I assume there are no codes since you didn't mention any? Have you checked the fuel trims or the fuel pressure?

How about checking for vacuum leaks? Often times pinging can be caused by a lean air fuel mixture.
 
It's worse in warm weather, yes. Never happens when the engine is cold. There are no codes.
The only thing I have had done (that I know about) are those things I listed. I think he said he had the scanner plugged in when he did a test drive but he didn't mention anything abnormal.
 
What year and what trim level of LANCER is your car?
Sounds like the timing has jumped a tooth or more. My quick research says it's a timing chain and 87 octane is Okay to use. The tensioner may possibly be in need of replacement or the chain may have stretched as well. Have you done any mods?
 
I had this happen to my sierra. The knock sensors weren't reading good and did that but to a lesser degree but enough to worry me. It didn't throw a code or even have a pending one but my mechanic knew what the issue was since he'd seen it many times before. New genuine sensors fixed it.

Did the knock sensors on my yukon later when they had no issue just to prevent it from happening. Use only the best parts for things like these, i went with genuine. I wouldn't touch the cheap crap for electrical stuff especially if it provides data to a computer. I know there's a way to test them but i don't remember how and they need to be removed anyway.
 
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